The present invention relates to a linear motor performing linear motion.
FIG. 19 illustrates a conventional linear motor. Tubular outer yoke 201 houses tubular inner yoke 203 having coil 202. Permanent magnet 204 is disposed between outer yoke 201 and inner yoke 203. Magnet 204 vibrates following the magnetic flux generated by inner yoke 203, so that a vibratorxe2x80x94fixing magnet 204xe2x80x94reciprocates.
The linear motor discussed above; however, has the following problems:
(1) The permanent magnet is fixed to the vibrator on its outer yoke side. The vibrator is thus positioned between the inner yoke having the coil and the permanent magnet. Thus a space between the inner yoke and the magnet becomes too wide. As a result, magnetic-flux-path incurs some loss. Further, the magnetic flux generated by the inner yoke changes greatly, so that eddy current is produced at a vibrator facing the inner yoke.
(2) The vibrator supporting the permanent magnet is non-magnetic body, thus when the vibrator is placed between the magnet and the yoke, non-magnetic-section other than the space is produced. This structure allows the non-magnetic-section to interfere with magnetic-flux for generating vibration, thus the vibrator cannot vibrate efficiently.
(3) Both the inner and outer yokes are formed by laminating electromagnetic steel in the circumferential direction, therefore, manufacturing them is a cumbersome work.
The objective of the present invention is to provide a linear motor, where a space between the permanent magnet and the inner yoke is provided as narrow as possible, the production of eddy current is thus restrained, and the yoke is easy to manufacture.
The linear motor of the present invention comprises the following elements:
(a) a tubular outer yoke;
(b) a tubular inner yoke disposed in the outer yoke;
(c) a coil provided to the outer yoke or the inner yoke;
(d) a permanent magnet vibrating between the outer and inner yokes following the magnetic flux generated by the coil; and
(e) a vibrator supporting the permanent magnet and made of magnetic material.
The magnetic-flux-loops produced by the outer and inner yokes travel through the vibrator without being hindered by the vibrator. As a result, the linear motor can vibrate efficiently.
Further, in the linear motor of the present invention, the permanent magnet is fixed to the vibrator on its coil side, so that the magnet is placed closer to the yoke on the coil side.
Still further, the linear motor of the present invention includes a plurality of coils in the inner yoke or outer yoke, and a plurality of permanent magnets on the side opposite to the coils of the vibrator. The plurality of permanent magnets arranged in the vibrator""s vibrating direction have unlike polarities adjacently. The vibrator has slits between adjacent magnets, so that leakage flux produced between unlike adjacent polarities can be prevented.
When the electrical resistance of the vibrator of the present invention is not less than 100 xcexcxcexa9.cm, the production of eddy current can be restrained.
The permeability of the vibrator of the present invention is preferably more than ten times of vacuum permeability.
The vibrator is preferably made of the material mainly comprising iron and chrome.
The vibrator is preferably made of the material including 80-90 wt % of iron and 10-20 wt % of chrome.
The vibrator is preferably made of the material mainly comprising iron, chrome and aluminum.
The vibrator is preferably made of the material including 75-88 wt % of iron, 10-20 wt % of chrome and 2-5 wt % of aluminum.
The vibrator is preferably made of the material mainly comprising iron and silicon.
The vibrator is preferably made of the material mainly comprising nickel and iron.
At least one slit is provided on a side of the vibrator, so that the production of eddy current is restrained. This slit may be long and narrow in the vibrator""s vibrating direction.
At least one electrically insulated section made of resin is provided on a side of the vibrator, so that the production of eddy current is restrained.
A compressor of the present invention comprises the following elements:
a linear motor including:
a tubular outer yoke;
a tubular inner yoke disposed in the outer yoke;
a coil provided to the outer yoke or the inner yoke;
a permanent magnet vibrating between the outer and inner yokes following the magnetic flux generated by the coil; and
a vibrator supporting the permanent magnet and made of magnetic material.
The compressor can be driven efficiently.
The linear motor of the present invention comprises the following elements:
(a) a tubular outer yoke;
(b) a tubular inner yoke disposed in the outer yoke;
(c) a coil provided to the outer yoke or the inner yoke;
(d) a permanent magnet vibrating between the outer and inner yokes following the magnetic flux generated by the coil; and
(e) a vibrator supporting the permanent magnet.
The permanent magnet is fixed to the outer yoke or inner yoke whichever includes the coil. This structure allows the permanent magnet to be placed closer to the yoke having the coil.
The compressor of the present invention comprises the following elements:
a linear motor including:
a tubular outer yoke;
a tubular inner yoke disposed in the outer yoke;
a coil provided to the outer yoke or the inner yoke;
a permanent magnet vibrating between the outer and inner yokes following the magnetic flux generated by the coil; and
a vibrator supporting the permanent magnet.
The permanent magnet is fixed to the outer yoke or inner yoke whichever includes the coil. This structure allows the compressor to be driven efficiently.
The linear motor of the present invention comprises the following elements:
(a) a yoke formed of compression-formed body made of metal magnetic particles;
(b) a mover vibrating along the yoke.
This structure allows the linear motor to be manufactured with ease.
The linear motor of the present invention may comprise the following elements:
(a) a tubular outer yoke;
(b) a tubular inner yoke disposed in the outer yoke;
(c) a coil provided to the outer yoke or the inner yoke;
(d) a permanent magnet vibrating between the outer and inner yokes following the magnetic flux generated by the coil; and
(e) a vibrator supporting the permanent magnet.
At least one of the outer yoke or inner yoke may be formed by compression-formed body made of metal magnetic particles.
The yoke of the compressed and molded body of the present invention may be made of metal magnetic particles and electrically insulated resin.
The yoke of the linear motor of the present invention may be a compression-formed body made of metal magnetic particles having an insulated layer on its surface.
The yoke of the linear motor of the present invention is formed by metal magnetic particles and its surface electrically insulated may be made of inorganic material.
The yoke of the linear motor of the present invention is divided in the cirumferential direction, so that the production of eddy current is restrained.
The yoke of the linear motor of the present invention is divided in the circumferential direction and an insulating layer is provided to the bonding face of the yoke. This structure allows the motor to further restrain the production of eddy current.
The compressor of the present invention comprises a linear motor including a yoke formed of a compression-formed body made of metal magnetic particles and a mover moving along the yoke.
The linear motor of the present invention comprises the following elements:
(a) a tubular outer yoke;
(b) a tubular inner yoke disposed in the outer yoke;
(c) a coil provided to the outer yoke or the inner yoke;
(d) a permanent magnet vibrating between the outer and inner yokes following the magnetic flux generated by the coil; and
(e) a vibrator supporting the permanent magnet.
At least one of the outer yoke or inner yoke is formed by arranging a plurality of laminated blocks in an annular shape, and a space between the adjacent blocks is formed by the compression-formed body.
The compressor of the present invention comprises the following elements:
a linear motor including:
(a) a tubular outer yoke;
(b) a tubular inner yoke disposed in the outer yoke;
(c) a coil provided to the outer yoke or the inner yoke;
(d) a permanent magnet vibrating between the outer and inner yokes following the magnetic flux generated by the coil; and
(e) a vibrator supporting the permanent magnet.
At least one of the outer yoke or inner yoke is formed by arranging a plurality of laminated blocks in an annular shape, and a space between the adjacent blocks is formed by the compression-formed body.